In recent months, dioceses around the world have been offering Catholics a spiritual benefit that fell out of favor decades ago — the indulgence, a sort of amnesty from punishment in the afterlife — and reminding them of the church’s clout in mitigating the wages of sin.

The fact that many Catholics under 50 have never sought one, and never heard of indulgences except in high school European history (Martin Luther denounced the selling of them in 1517 while igniting the Protestant Reformation), simply makes their reintroduction more urgent among church leaders bent on restoring fading traditions of penance in what they see as a self-satisfied world.

“Why are we bringing it back?” asked Bishop Nicholas A. DiMarzio of Brooklyn, who has embraced the move. “Because there is sin in the world.”

Like the Latin Mass and meatless Fridays, the indulgence was one of the traditions decoupled from mainstream Catholic practice in the 1960s by the Second Vatican Council, the gathering of bishops that set a new tone of simplicity and informality for the church. Its revival has been viewed as part of a conservative resurgence that has brought some quiet changes and some highly controversial ones, like Pope Benedict XVI’s recent decision to lift the excommunications of four schismatic bishops who reject the council’s reforms.

The indulgence is among the less noticed and less disputed traditions to be restored. But with a thousand-year history and volumes of church law devoted to its intricacies, it is one of the most complicated to explain.

According to church teaching, even after sinners are absolved in the confessional and say their Our Fathers or Hail Marys as penance, they still face punishment after death, in Purgatory, before they can enter heaven. In exchange for certain prayers, devotions or pilgrimages in special years, a Catholic can receive an indulgence, which reduces or erases that punishment instantly, with no formal ceremony or sacrament.

When it’s all said and done, the whole idea of indulgences comes down to the idea that Christians must undergo a process of temporal punishment before they are allowed to go to heaven. But Scripture doesn’t teach that. Rather, the punishment process was completely absorbed for us by Christ on the cross. We may receive discipline from our Father, but we will never again receive any form of punishment. Scripture no where hints that those who are united to Christ are in two categories and locations: those undergoing purificatory punishment in Purgatory and those in their heavenly home. All who die in Christ go to be with the Lord. Thanks be to God who clothes us with his righteousness and took all of our punishment.